Ore concentration.



GEORGE ALBERT CHAPMAN AND STANLEY TUE) innit It. OF LONDON, ENGLAIID, ASFSIGNORS TO MINERALS SEPARATION LIMITLD, 01: lLOlIlDOhl, ENGlLhUI).

ORE CONCENT'R ATION.

No Drawing.

Specification of Letters Patent.

T 0 all whom it may concern Be it known that We, Gnonon itnnun'r- CHAPMAN and STANLEY TUCKER, subjects of the King of England, and both residing at London, llngland, have invented certain new.

and useful li'nproveihents in Ore (micentratic-n, of which the following a specifica- February 1908, and 962,678, of June 528,

In some cases and :tor various reasons it is disadvantageous to use an acid such as sulfuric acid. Thus the acid may not be readily. obtainable or may be expensive or, for example with; ores containing carbonates such as calcite, the acid may be rapidly consumed.

It has been proposed in a flotation process as for example as described in United States Patent No. 835,120 mentioned above, wherein acid is used, not for its chemical action, but for its physical efl ect, to use in place of the acid an acid salt, and also it has been proposed, in processes wherein acid is used for its chemical action, to treat an ore by introducii'ig itinto a hot solution containing sulfuric acid or salt cake or a bisullt'ateol? an alkali metal for the purpose of effecting the flotation of the sullids by gas chemically generated by the acid without the employment of any selective agent or any mineral frothing agent.

According to this invention, a process for the concentration of metalliferous ores consists in agitating the ore with Water contain ing a selective agent or a mineral frotliing agent and containing also a bisulfate of an alkali metal or a mixture of a normal sul- "fate of an alkali metal and sulfuric acid, separating the metalliferous matter by flotation, and thereafter treating the liquor with free acid to brine it back to its original con dition and using it with or without a Further quantity ol the selective agent: or mineral trothlng agent tor the treatment ol' a tin ther quantity ot ore. Also, aetarriling to this invention. an ore containing a carbonate decomposable by sul'l'urio acid may be treated by subjeeling it to agitation and to the action ol a selective agent or a mineral i'roihinp' agent in the presence ojl a bisultate of an alkali metal or ol :1 normal sultate of an alkali metal and sullfurio acid.

When the acid generally employed replaced by a bi -ullate ol an alkali metal, it is Found that with a closed circuit, that is to .'-l. uringr the same oireuil liquor riaieatodly, the super-normal arid radical is slowly consinned, lea ring: normal sultate. The sulfuric acid (H t- 0,) in lig 'ht combination with normal sultan (l(:i. ,t"lt),) in the bisultate Nails-1th) will throughout the specification be rel'tn'rrd to as the available sulturic acid. in the course ol the process the available sull'urio acid is consumed it the orc contains car-Inmates or the like, but is consumed comparatively slowly and not until the acid has had time to elleet its desired physical action. To bring; the liquor baelc into the desired condition, we add :l'rce sulturic acid and lightly agitate to Qet the same ell'ect as a solution ol bisullate ol soda. In each case the etlecl is to retard the consumption of the sulluriiacid, no doubt owing to what is known as the balanced action.

-l"he degree ol advantage in using bisull'ale instead ot sull'urie acid. varies in diflerent i-ireumstanees. For example, musing essential oils as l'rothin r agents, the advantagg'es ol bisull'ate over acid are not so marked, as with other 'l'rolhiug' agents, and indeed, with essential oils, acid can frequently be omitted with advantage, as men tioned 'l'or example in lritish Patent No 21,857 ol' lllttl. i

The process of eom-enlrating ores according to this invention is more particularly ap plieable to the com-entration ot a calcite blcnde ore, that is, an ore containing: car bonates. in one case we have investigated ot a calcite blende ore, the ordinary process of concentrating the ore by the llotation method is to agitate it, al'ter crushing, in

four times its weight ol water at about (10 C. with about one and one-half lbs.

Patented l l'ov. l to, .lllltift.

Application filed Jul /'30. 1912. Serial No. 71 2305).

I aerator per ton (0.067%) of an oily frothing agent.

About 120 lbs. of acid per ton of ore must. be added to insure a clean flotation and this is disadvantageous because of the high acid consumption and because sulfuricacid suddenly and rapidly attacks the'carbonates, iuterfering with good concentration.

The following is a description by way of example of one method of carrying this invention into effect. The ore, a zinc-lead ore, tobe treated, is mixed with Water containing preferably about 1% of commercial bis'ulfate of soda (1?. e. the H SO, radical beyond the Na SU. is equivalent to 36 lbs. of H 80 per ton of ore, or 1.6%), and 1-1- lbs. per ton of ore (0.067%) of wood tar oil and Texas fuel oil mixed in equal volumes. The mixture is agitated for about one-half minute at 55 C. and discharged into a spitzkasten where the froth which floats is removed with a. certain quantity of water. The tailings from the spitzkasten are drawn into a second mixing vessel, agitated with a further quantity of wood tar oil and Texas fuel oil, and discharged into a second spitzkasten where a second froth is removed. The tailings are retreated in a third mixing vessel and so on, theoperation being preferably carried out in the apparatus described in the prior Patent No. 979,857, of December 27, 1910.

4 .The liquid, passing off from the spitzkasten with the frotln-is separated from the solid particles contained therein. and is returned to the circuit for the treatment of a 'further quantity of ore. In many cases the bisulfate of soda used is'eouivalent to the use of 36 lbs. per ton of ore (1.6%) of available sulfuric acid and. the consum-ption is less than this. When the liquid is returned to the circuit, sufficient sulfuric acid is added thereto to bring the quantity of available sulfuric acid back to the 36 lbs. per ton prescut in the original amount of bisulfate employed.

In the ordinary processof concentrating ores by froth flotation, a much larger percentage of acid would be necessary to insure a clean flotation than the 1.6% mentioned above, in some cases being as much as 10%.

The following is a description by way of example ofanother method of carrying this invention into effect: 400 guns. of a sample of San Francisco 'del Oro-was agitated with 1600 c. cs of water containing 1% of bisulfate of soda, the equivalent of 36 lbs. per ton of available sulfuric acid and 1 lb. of camphor oil together with 1 lb. of wood tar oil per ton of ore. the temperature being that of the atmosphere. The recovery of zinc contents in two treatments was 77.6% and of the lead contents, 52.1%, the concentrates assaying zinc, 39.7% lead 14.8%, insolublesvention into ell'ect when normal sodium sulfateaifd sulfuric acid are employed. The

ore contained argentiferous. galena (about 13%) blende (about 30%) associated with quartz and tluor-spar. In 1600 c. c. of water were dissolved 21.5 grs. of Glauber salt 'Na SUAOI-LO and GT5 grs. n so... This mixture was a gitated at C. to effect uniform solution. 400 grs. of ore were added immediately followed-by 0.0 1% of camphor. oil (equivalent to one pound per ton of ore) and 0.007 amylacetate (equivalent to 0116 lbs. per ton of ore). This mixture was agitated for one minute and one froth removed gave a recovery of 85.7%' of the zinc contentand 57.3% of the lead content; an assay of the concentrate showed 37.3% of zinc, 13.9% v

of lead and 3.0% of insolubles. It will be seen that-in this test the amount of available sulfuric acid used was about 1.6% on the ore, and the consumption was less than this Whereas in using sufuric acid. in the ordi-- nary Way more than 10% of sulfuric acid is necessary to insure any clean flotation, because sulfuric acid by itself suddenly and rapidly attacks the carbonates.

An example of this invention as applied to film flotation, will now be described: 400

grins. San Francisco del Oro orecrushed-to d0 mesh,was agitated with 1600 c.'-- c. of

water at atmospheric temperature Containj 'ing Glauber salt and sulfuric acid equiva-. lent to 1% of bisulfate of soda, and 5 lbs. per ton of Texas fuel oil, for one minute/ The resultant pulp was floated at atmospheric temperature.

In carrying this invention into practice part of the metalliferous' constituents may -be separated by the process described in the previous Patent No. 879,985, hereinbefore mentioned.

It is found that the. sodium bisulfate has the same physical effects as the sulfuric acid commonly employed in such processes, that is to say. it enables a sufficient recovery to be made but no rapid consumption of the reagent is noticeable and the same circuit. liquor can be repeatedlv used. Potassium Ezisulfate has the same effect assodium bisulate.

, In the processes above referredto thedetails of practical operation may be varied. Thus the pulp may be at atmospheric temperature or may be heated to any suitable degree according" to the conditions. The naiii ture of the. frothing agent and the stage or of further quantities of agents.

In carrying this invention into effect it is tobe understood that the bisulfate may be formed ocequivalent efl'ects obtained by adding normal sulfate and sulfuric acid to the ore pulp.

What we claim as our invention and desire to secure by Letters Patent is 1. A process for concentrating ores, which consists in subjecting to agitation and to the action of a selective agent a pulp ofan ore containing a carbonate, in .the presence of a bisulfate of an alkali metal, and separating the selected portion of the ore.

J 2. A process for concentrating ores, which consists in subjecting to agitation and to the action of a selective agent a pulp of an ore containing a carbonate, in the presence of a sulfate of an alkali metal and sulfuric acid, and separating the selected portion of the ore.

3. A process for concentrating ores, which consists in subjecting an ore pulp to agitation and to. the action of a selective agent,

, in the presence of a bisulfate of an alkali metal, separating the selected portion of the ore and solid residue from the liquor, and returning the liquor in closed circuit with the addition of sulfuric acid for the treatment of a further quantity of ore.

4. A process for concentrating ores, which consists in subjecting an ore pulp to agitation and to theaction of a selective agent,

.in the presence of a sulfate of an alkali metal and sulfuric acid, separating the selected portion of the ore and solid'residue from the li uor, and returning the liquor in closed circu t with the addition of sulfuric acid for the treatment of a further quantity po fore. i e5 "5. A processfor concentrating ores, which consists in subjecting to agitation and to the action of. a selective'agent the pulp of an ore containing a carbonate, in the presence of a bisulfate of an alkali metal, separating the selected portion of the ore and solid residue from the liquor, and returning the liquor in closed circuit with the addition of sulfuric acid for the treatment of a further quantity of ore. i

6. A process for concentrating ores, which consists in subjecting to agitation and to the action of a selective agent a pulp of an ore containinga carbonate, in the presence of a sulfate of an alkali metal and sulfuric acid, separating the selcctcdportion of the ore and solid residue from the liquor, and returning the liquor in closed circuit with the addition of sulfuric acid for the treatmcntot' a further quantity of'orc.

T. A process for concentrating ores, which consists in agitating a pulp of an ore containing a *arhonate to heat in air and form a mineral froth in the presenceo'l small proportions of a bisulfate of an alkali metal and a mineral frotliing agent, and separating the froth produced.

8. A process for concentrating ores, which consists in agitating a pulp of an ore containing a carbonate to beat in air and form a mineral froth, in the presence of small proportions o'E a sulfate of an alkali metal and sulfuric acid and a mineral fret-hing agent, and separating the froth produced.

9. A process for concentrating ores, which consists in agitating an orc pulp to beat in air and form a mineral froth in the presence of a small proportion of a bisulfate of an alkali metal and a mineral frothing agent, separating the froth produced, treating the liquor with free sulfuric acid, and using it with the addition of a further quantity of the mineral frothing agent for the treatment ofa further quantity of ore.

I 10. A process for concentrating ores, which consists in agitating an ore pulp to beat in air and form a mineral froth in the presence of a smallproportion of sodium bisulfate and a small proportion of a mineral frothing agent consisting oi a mixture of wood tar oil and Texas fuel oil, separating the froth produced, treating the liquor with free sulfuric acid, and usingit With the addition of a further quantity of the mineral 'l'rothing agent for the treatment of a further quantity of ore;

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

GEORGE ALBERT CHAPMAN. STANLEY TUCKER. \Vitnesses:

Annular OWEN Hummus, O. J. WVon'rrI. 

